THE THIGH. 



281 



the thigh, and of the hinaer leg gene- 

 rally ; for they are all inserted into 

 the bone of the knee, and that is 

 connected by strong tendons with 

 the bone of the true leg. 



On the inside of the thigh are 

 several other large fleshy muscles, 

 which will be easily recognized on 

 the thigh of the living horse. First 

 is a long, narrow, prominent muscle, 

 the sartun'us, d, arising partly from 

 the lumbar vertebra?, and extending 

 down the thigh — assisting in bind- 

 ing the leg, and turning it inward — 

 giving it a rotatory motion, and also 

 aiding in many of the natural actions 

 of the horse. 



Next comes a broad, thin muscle, 

 the gracilis, e, occupying tiie greater 

 portion of the surface of the inner 

 part of the thigh, and particularly 

 the prominent part of it. It arises 

 from the lower portion of tho 

 liaunch-bone, and, in its passage 

 downward uniting with the last 

 muscle, is inserted with it into the 

 inner and upper part of the tibia. 

 It acts with great mechanical disad- 

 vantage, but its power is equal to 

 the task. It bends the leg, and 

 rotates it inward. 



Still, on the inside of the thigh, 

 and forming the posterior edge of 

 the thigh inwards, and contributing 

 much to its bulk, is another import- 

 ant muscle, the pcctineus. Part of 

 it acts with very great mechanical 

 advantage, and powerfully flexes the 

 thigh on the pelvis, and lifts and bends the leg. It is one of the most effectual of 

 the extensor muscles. Considering the weight of limb which it has to raise and 

 flex, it had need to possess great power. 



We now turn to some of the muscles that are evident to the eye on the outside ot 

 the thigh. 



First is the glutaeus extermis, situated in the middle of the external part of the 

 haunch. It is of a triangular figure, attached to the antero-superior and to the inferior 

 spines of the ilium, and is inserted into the smaller outer prominence of the upper bone 

 of the thigh. Next is the great glutasus muscle, arising from the spinous and transverse 

 processes of several of the bones of the loins, and from the sacrum, and from the dif- 

 ferent edges of the ilium, and inserted into the great protuberance of the upper bone 

 of the thigh (page 68), behind and a little above the joint that unites the thigh to the 

 haunch-bone. It is seen at c, in the cut on the following page. It constitutes the 

 upper and outer part of the haunch, and gives that fulness and roundness to it which 

 good judges so much admire in the quarters of the horse. It is one of the main 

 instruments in progression. When the thigh has been brought forward under the 

 body by the muscles already described, the plain action of these gluta?i muscles is to 

 extend the haunch, and force or project the body onward. To effect this, they must 

 be very powerful, and therefore they are so large, and rise from such an extensive 

 surface. They ought, also, to act at great mechanical advantage, and so, in one 

 sense, they do. Springing from the loins and the ilium, and the sacrum, they act 

 almost in a right, or perpendicular line ; in that line in which we haie seen that the 

 greatest power is gained. 



24* 21. 



